wedekind



(No Model.) 2'Sheets-Sheet 1.

J. O. WEDEKIND.

MILLSTONE. No. 297,889. Patented Apr. 29, 1884.

WITNESSES: INVBNTOR flfiw ATTORNEYS? (No Moms)- 2 Sheets-Sheet 2.

J. C..WEDEKIND.

MILLSTONE. v No. 297,889. Patented Apr. 29,1884.

k WITNESSES:

@zzf M N. PETERS. Fholwulha n iwr. Washington. Dv C.

i To all whom it may concern.-

UNITED STATES PATENT OFFICE.

JOHANN CARL WEDEKIND, or NORDHAUSEN, Pnussm, enniumvv.

MILLSTONE.

SPECIFICATION forming part of Letters Patent No. 297,889, dated April 29, 18.84.

Application filed November 8, 1883. (N 0 model.)

Be it known that I, J OHANN CARL WEDE:

'KIND, a subject of the Kingdom of Prussia, 1

German Empire, residing at the city of Nordhausen, in the Kingdom of Prussia, German Empire, have invented certain new and useful Improvements in Millstones, of which the following is a specification.

This invention has reference to certain improvementsin millstones, whereby the face of the millstone is effectively ventilated, so as to prevent the heating of the flour, and by which a more perfect grinding 0f the cereals or other substances takes place.

The invention consists of a millstone the face of which is provided with smooth or grooved lands that alternate with inclined ventilating-sections, which are arranged tangential to the eye of the millstone. The inner ends of some of the ventilating-sections are connected with vertical channels, which communicate with inclined channels that extend diagonally through the stone, and are provided at their upper ends with hoods. The outer ends of the ventilating-sections are providedwith grinding-faces concentric to the eye of the stone. The eye of the stone is lined with sheet metal, and provided with a vertically-sliding sleeve, through which air is supplied to the ventilating-channels.

In the accompanying drawings, Figure 1 represents a vertical transverse section on line 3 y, Fig. 3, of my improved millstone. Fig. 2 is a side elevation; Fig-'3, a bottom view; Fig. 4, a top view of the same; and Figs. 5, 6, 7, and 8 are respectively avertical central section on line a; as, Fig. 7, side, bottom, and top views of a modified construction of my improved millstone.

Similar letters of reference indicate corresponding parts.

My improved millstone is provided with an eye, A, of considerable size, which'is lined with a metallic cylinder, A. A number of tangential ventilating-sections, a, extend from the eye outward to or toward the skirt of the stone, said sections increasing in width and decreasing in depth from the eye outward. The ventilating -sections a alternate with smooth or grooved lands b b, which are also tangential to the eye A. The sections a serve for the purpose of supplying currents of air to the faces of the runner and bed stone and to the substances to be ground, so that the latter are distributed quickly and uniformly over the grinding-surfaces. The greater the inclination of the ventilating-sections a from the eye toward the skirt of the stone the quicker is the distribution of the substances to be ground. The inclined ventilating-sections a a terminate at the skirt of the stone in horizontal or nearly horizontal grinding-sections a,

concentric to the eye A, by which thedistribution of the material is checked and the same prevented from passing off too quickly at the skirt of the stone. As air is continuously supplied to the grinding-sections c and to the substances to be ground, a more effective and cooler grinding action takes place.

In the millstone shown in the drawings, a runner with six ventilating sections a is shown, said runner having a diameter of I about three feet. According to the greater or smaller diameter of the stone, a greater or smaller number of ventilating-sections is employed. The faces of the lands 1) b are dressed parallel to the edge of the next succeeding ventilating-sections a a, and at an angle to the preceding ventilating-sections, so that the inner ends of the furrows open toward said sections, said furrows being of greater or less depth, according to the quantity of air to be supplied to the lands. The inner ends of these lands are smooth, as shown at d d. The outer grinding-sections, c, of the ventilating-channels are made of greater or smaller width, and dressed either smooth or grooved, or alternately smooth and grooved, as required. The lands 1) b of the stone are either integral with the stone or formed of separate, removable,

and interchangeable grinding-plates. When the stone is to grind cereals, it is preferable to use porous and hard grinding material, while for grinding bones, ores, and similar hard substances it is preferable to use hard and firm material, with the exception of the inner portions, which can be selected of a somewhat softer material, as the surface of the same is not used so much for grinding as for conducting the. materials and spreading them over the lands.

' By makingthe grindingplates interchange able my improved millstone construction is also adapted for the pulverizing of hard substances. XVhen the substances have to be ground to a high degree of fineness, there are arranged at the inner ends of the tangential ventilating-sections a a vertical air-channels e, of triangular shape, that extend vertically through the eye A of the stone, and communicate at their upper ends with a depression, 9, concentric to the eye A. Inclined air-channels e extend from the lower part of the vertical air-channels e diagonally in upward direction through the stone, and are provided at their upper ends with hoods f, the openings of which are placed in the direction of motion of the stone, so as to take up the air and conduct it in currents of considerable strength through the inclined channels c and channels 6 to the ventilating-sections a a.

If desired, the substances to be ground can be fed, instead of through the eye, through the vertical channels 0 directly into the ventilating-sections a a.

In the drawings three such channels are shown next adjoining the lining of the eye at the inner end of every second ventilating-section a. The material in the channels e is acted upon by the air-currents passing down through the inclined channels 0, and is thus propelled forward and forced through between the grinding-surfaces of the stones. The regular feeding of the material to the channels 6 e is kept up by a scraper (not shown in the drawings) that moves in the depression 1 at the top of the stone.

In place of the vertical channels 0 and their inclined air-supply channels e, may be arranged diagonallyinclined air channels h, that pass from the top of the stone downto the bottom of the stone, and communicate at their lower ends with the ventilating-sections a a, as shown in Figs. 7 and 8. The lower ends of the inclined channels h may be arranged with screens i, if desired, for the more even distribution of the air. The edges of the bottom openings of the channels it are made either straight or rounded off toward the lands. If the material is conducted to the grinding-faces through the channels it h, the screens i are dispensed with, and the material is wiped by the scraper moving in the depression 7 into the inclined channels h.

Another auxiliary means of supplying and increasing the air-currents consists in an extensible sleeve, A, of the eye of the stone, which sleeve is made of double-layer sheetiron, and adapted to be raised or lowered in the lining of the eye, so as to increase or decrease the air-draft. The raising of the sleeve or tube A" diminishes the inward draft of air, and the lowering thereof increases the same. This is the simplest mode of ventilating the tangential sections a a of the stone, and is used either singly or in connection with the separate air-channels e e, that are designed to augment the draft.

The grinding operation may be either completed in one operation by one pair of stones, or, preferably, by the use of a number of stones, through which the substances to be ground are successively conveyed, according to the different degrees of reduction. For hulling and working off the exterior skin of grain, &c., for instance, it is necessary to use lighter stones, while for grinding very fine, heavierstones and larger grinding -surfaces are requircd.

My improved construction of millstone is adapted for all the different systems of milling, and for grinding coarse as well as finer grades of flour. The eye of the bed-stone is not rounded off or worked out as that of the runner, but arranged at right angles to the face of the stone. The ventilating air-channels, which are also arranged tangential to the radius of its eye, terminate a short distance from the eye, so as to attack and distribute better the material in connection with the sharp-pointed inner ends of the lands of the runner.

For dressing the lands of the runner, it is preferable to draw a circle the radius of which is equal to about one-half of the radius of the stone, and then dress the lands with furrows parallel to the adjoining edges of the succeeding ventilating-sections and at angles to the adjoining edges of the preceding ventilatingsections, so that the inner ends of the furrows open toward the ventilating-sections in advance of the lands, to receive the currents of air therefrom, as shown clearly in Fig. 1.

In the bed-stone the furrows of the lands and ventillating sections are made of less depth than those of the runner, while for some purposes the furrows are not required at all. The runner requires to be frequently inspected, so as to keep the dress of the lands in proper order and cause it to do efficient work.

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. A millstone provided with tangential lands and intermediate tangential inclined ventilating-sections, the latter increasing in width and decreasing in depth from the eye toward the skirt, and with vertical air-channels extending from the inner ends of said ventilating-sections to the upper face of the stone, and with a concentric depression in the upper face of the stone, substantially as described.

2. A millstone provided with tangential lands, intermediate tangential inclined ventilatingsections, the latter increasing in width and decreasing in depth from the eye toward the skirt, vertical air-channels extending from the inner ends of said ventilating-sections to the upper face of the stone, and with inclined air-channels extending from the upper face of the stone to the lower ends of said vertical airchannels, substantially as described.

3. A millstone provided with tangential lands, intermediate tangential inclined ventilating-sections, the latter increasing in width and decreasing in depth from the eye toward the skirt, and with vertical air-channels and inclined air-channels extending from the upper face of the stone to the lower ends of said vertical air-channels, said inclined channels being provided with hoods at their upper ends, substantially as described.

4. A ,millstone provided with tangential lands and intermediate tangential inclined ventilating-sections, the latter increasing in width and decreasing in depth from the eye toward the skirt, the furrows of said lands being parallel to the succeeding ventilatingsections, and the inner ends thereof opening toward the ventilating-sections in advance of the lands, substantially as described. I

5. A millstone provided with tangential lands, intermediate tangential inclined ventilating-sections, the latter increasing in width and decreasing in depth from the eye toward the skirt, and with concentric grinding-surfaces at the outer ends of the ventilating-secends of the supply-channels e e to the top of the stone, and having hoods f f at the top of the stone, substantially as described.

In testimony whereof Ihave signed my name to this specification in the presence of two subscribing witnesses.

JOHANN CARL WEDEKIND.

WVitncsses:

AUGUST MURNE, G. HARRISON SMITH. 

